142 Mr. W. J. Lewis's Crystallographic Notes. 



(1 0, 1 1) = 40° 51f, (1 1, 1) = 28° 27f, 

 (010, 111) = 62°45§ / ; 



a:&:c=l"0802: 1 : 0-7869. 



Calculated. Observed. 



It 71° 0' 70° 34ito70 27 



Ik 34 24J 34 36 „ 34 14 



tk 46 15 46 11 „ 45 54 



rbm 44 42 44 50 „ 44 36 



I bp 63 Hi 63 13 „ 62 52 



\b (4 1 0) 75 49 J 76 „ 75 45 



Uim, 89 24 89 37 





Z 57 51f 57 56 



ml 122 8£ 121 49i 



'mjt 74 49 74 58 „ 74 52 



m t t 105 11 105 6 ,,105 10 



mk 61 24^ 61 52 „ 61 34 



mk 118 35| 118 10 



m 



k 89 17 



bl 90 89 53i 



Vbk 69 47^ 69 32 „ 70 3J 



U*, (over 01) 40 25 40 13 



Jordanite. — On a crystal of blende from the Binnenthal in 

 the British Museum two small crystals, the one of Jordanite, 

 the other of Binnite, are implanted. The former, on measure- 

 ment, was found to be a combination of the forms {0 01}, 

 {119}, {113}, {225}, {112}, {110}, {013^, {0 2 5}, 

 {012}, {0 2 3}, {011}, {312}, {311}, {310}. Of these 

 the forms {2 2 5}, {0 2 5}, {0 2 3}, {3 1 2}, {3 1 0} are, I be- 

 lieve, new. The middle index in these symbols corresponds 

 to the brachydiagonal usually denoted by the letter y and the 

 parameter b. This arrangement is not to be confounded with 

 that of Professor vom Rath, in which b corresponds to the 

 makrodiagonal and a to the brachydiagonal. The angles be- 

 tween some of these planes observed and calculated from the 

 elements, c : ^0 = 65° 0'; Jo : ^o = 50 49', given by Prof, 

 vom Rath are : — 



